Refrigerating apparatus



0d. 25, 1938. B, M, BUCHANAN 2,133,964

REFRIGERATING APPARATUS Filed April 1, 1937 F'lah.

mvENToR Lzsuz B.M.BucHANAN.

BY ATToR Patented Oct. 25, 1938 UNITED STATES PATENT OFFICE BEFRIGERATING APPARATUS Leslie B. M. Buchanan, Springfield, Mass., assignor to Westinghouse Electric & Manufacturing Company, East Pittsburgh, Pa., a. corporation of Pennsylvania Application April 1, 1937, Serial No. 134,230

12 Claims.

My invention relates to refrigerating-a-ppratus and has for an objeci-I to provide improved apparatus of this kind.

A further object of the invention is to provide improved refrigerating apparatus employing expansion devices having elongated passages, commonly referred to as capillary tubes.

A further object of the invention is to selectively vary the amount of refrigerant passed by an expansion device of the capillary tube type in accordance with the requirements of the evaporating means.

A still further object of the invention is to provide an improved two temperature refrlgerating system having evaporators operating at different temperatures and supplied with refriger ant by expansion devices of the capillary tube type.

Another object of the invention is to prevent passage of gas through the capillary tubes from the condenser to the evaporators of a multievaporator refrigerating system during inactive periods of the refrigerant circulating means.

These and other objects are effected by my invention as will be apparent from the following description and claims taken in connection with the accompanying drawing forming a part of this application, in which:

Fig. 1 is a diagrammatic view of a refrigerating system constructed and arranged ln accordance with my invention Fig. 2 shows a second embodiment of the refrigerant connections between the evaporators of systems constructed in accordance with the invention; and,

Fig. 3 shows a, modified form of the thermostatic control apparatus of Fig. 1.

While my invention is applicable to various forms of refrigerating systems having one or more evaporators-supplied with condensed refrigerant by expansion devices of the capillary tube type, I have chosen to disclose it applied to two temperature systems of the type shown and claimed in my copending application, Serial No.

l 15,003, filed April 6, 1935 and assigned to the assignee of the present application.

Referring now to Fig. l of the drawing, I have shown low and high temperature evaporators Ill and II, respectively, connected in the manner disclosed in the aforementioned application and described in detail hereinafter, which evaporators are supplied with refrigerant by a condensing unit. generally indicated Vat I2. The evaporator I0 is employed for cooling the air in a low. temperature chamber I3, formed in a cabinet structure I4, and for freezing or congealing liquids which may be contained in trays at I5. The evaporator III may be formed with refrigerated shelf portions I6 for supporting the trays I5. A manifold I1 for refrigerant is disposed adjacent the top of the evaporator I0, as shown.

The evaporator II, which preferably is provided with fins I9, functions to cool the air in a relatively high temperature refrigerated chamber I8 in which food products are stored. The evaporator II is so proportioned that it is operated at a relatively high temperature, whereby ex cessive dehydration of the air in the food storage chamber I8 is prevented. The evaporator III is operated at a, temperature below freezing for facilitating the congelation of the fluid in the trays I5 and for preserving frozen food products stored in the chamber I3. Inlet and outlet manifolds 2I and 22 are formed in the evaporator II, the former being connected by a conduit 23 to the manifold I I of the low temperature evaporator I0.

The condensing unit I2 includes, preferably, a compressor 24, driven by an electric motor 25, and a condenser 2B. Refrigerant vapor-ized in the evaporators I0 and II is Withdrawn by the compressor through a suction conduit 2l and is compressed to a relatively high pressure. I'he high pressure vapor is delivered through a conduit 28 to the condenser 26 in which the vapor is cooled and condensed. The condenser may be cooled in any well known manner such as, for example, by a fan 29.

Condensed refrigerant is conveyed from the condenser 26 to the manifold I'I in a manner to be described hereinafter. The condensed refrigerant entering the manifold Il passes preferentially to the evaporator I0 and will enter the connecting conduit 23 and evaporator II only after the evaporator III Is full. The charge of refrigerant in the system is such that the evaporators I0 and II are lled when all of the charge is circulated and, therefore, vaporization is eifected, primarily, in the higher temperature evaporator II. As the evaporator IU is normally maintained at a lower temperature, substantially no vaporization is effected therein and, as it is filled with liquid refrigerant, vapor generated in the higher temperature evaporator Il is prevented from entering the low temperature evaporator I0 and condensing therein.

Vaporization of refrigerant in the low temperature evaporator IIJ is effected by reducing the amount of refrigerant in the low side of the system so that condensed refrigerant is present in only the low temperature evaporator I0. This operation is effected by wlthholdng from circulation a quantity of condensed refrigerant equivalent to the quantity present in the high temperature evaporator when itis active plus the quantity required to i'lll the vapor space in the low temperature evaporator when it is active. The withheld refrigerant is stored in the high side of the system in a suitable reservoir or in the condenser. At this time, vaporation is effected at low pressure in the evaporator I3 and substantially no cooling is effected by the evaporator as it contains only gaseous refrigerant discharged by the evaporator ||l.

'Ihe connections between the evaporators in Fig l for conveying refrigerant is shown by way of example and it will be understood that they may be connected in other suitable manners. For example, the low and high temperature evaporators may be connected in series, as shown in Fig. 2. The low temperature evaporator is shown in this figure at Illa and receives refrigerant from the capillary tube 35, the latter being connected to the bottom of the evaporator Ia, as shown at 35a, so that refrigerant passes through the evaporators l|la and in series. The other portions of the system may be similar to those shown in Fig. 1 and elements shown in both gures which are common thereto are indicated by similar numerals.

The apparatus described in the foregoing is disclosed and claimed in my aforementioned oopending application. It will be apparent to those skilled in the art that the system operates on the well known compressor-condenser-expander cycle so that further detailed description of the operation is not necessary.

In accordance with my invention, improved means including expansion devices of the capillary tube type are employed for conveying the condensed refrigerant to the evaporators and Il. A reservoir 3| is provided for storing condensed refrigerant during periods when the low temperature evaporator ||l is active and receives refrigerant from the condenser 26 through a conduit 32. A capillary tube 33 having serially connected portions 34 and 35 provides communication between the reservoir 3| and the manifold 1. Preferably the capillary tube 33 connects with an open topped conduit 36 that communicates with an upper portion of the reservoir 3| and determines the amount of refrigerant that is stored therein.

A second tube 31 provides communication between the bottom of the reservoir 3l and the portion of the capillary tube 33 intermediate its portions 34 and 35. Flow of refrigerant from the reservoir 3| through the tube 31 is controlled, preferably, by a valve 38 actuated in any suitable manner as by a solenoid 39. The valve 3B is normally biased by a spring 4| to its open position, as shown, and it is closed upon energization of the solenoid 33.

The tube portions 34 and 35 define a high resistance expansion device for the liquid refrigerant .passed to the evaporator |0 during its active periods. At this time, the pressure difference prevailing between the high and low sides of the system is high so that a tube having high resistance is necessary for conveying substantially the same amount of refrigerant to the evaporator asis condensed. When vaporization is effected at relatively high pressure in the evaporator the pressure dlierential between the high and low sides of the system is relatively low and, therefore, the resistance of the expansion tube must be relatively low, otherwise refrigerant will be condensed faster than it is delivered by the expansion device with consequent backing up of liquid in the reservoir, and, therefore, starving the high temperature evaporator. Accordingly, the tube 31 is formed to offer less resistance to the passage of refrigerant than the tube portion 34 so that the total resistance of the tube 31 and tube portion 35 is less than the total resistance of the tube portions 34 and 35.

During periods when the solenoid 39 is deenergized, and the valve 38 is open, condensed refrigerant entering the reservoir 3| passes through the tube 31 and the portion 35 oi the capillary tube 33 to the evaporators I0 and Il. Accordingly, both evaporators Ill and contain liquid refrigerant and vaporization at relatively high pressure and temperature is effected in the evaporator Il during operation of the compressor 24 as described heretofore. At this time, some gas may escape from the resorvoir 3| through the portion 34 of the tube 33 but this will be negligible as the pressure prevailing between the ends of the tube portion 34 will be substantially equalized by the tube 31 and the portion 34, furthermore. offers very high restriction to the flow of gas.

Energization of the solenoid 39 closes the valve 38 whereby condensed refrigerant collects in the reservoir 3| to a depth determined by the elevation of the tube 36 and this quantity of refrigerant is withheld from circulation. Accordingly, the amount of refrigerant in the low yside is suincient to fill only the evaporator |0 and vaporization therein is effected at low pressure during operation of the compressor 24.

The thermostatic control apparatus will now be described. The source of electric power for the motor 25 and the solenoid 39 is represented by line conductors L1 and Lz, one terminal of the motor 25 and the solenoid 39 being connected to the conductor Li, as shown. Low and high temperature thermostats 42 and 43 may be suitably disposed within the chambers I3 and I3, respectively, for controlling the operation of the motor 25 and the solenoid 39. The thermostat 42 includes switches 44 and 45 that are closed When a predetermined high temperature prevails in the chamber |3 and are opened in response to a. predetermined low temperature therein. The thermostat 43 includes a switch 45 that is opened and closed in response to predetermined low and high temperatures Within the chamber, IB, re-

spectively.

The opposite terminal of the motor 25 is connected by a conductor 41, having the switch 46 connected therein to the line conductor L2. A branch conductor 48, controlled by the switch 45 connects the conductor 41 to the line conductor L2, so that the switches 45 and 46 control energization of the motor 25 in parallel. The opposite terminal of the solenoid is connected by a conductor 49 having the switch 44 connected therein, to the line conductor La.

Operation As shown in Fig. l, the thermostat switches 44, 45, and 46 are open as the temperatures prevailing in the chambers I3 and i8 are below values at which the thermostats 42 and 43 effect closing thereof. 'I'he valve 38 is therefore open, the solenoid 39 being deenergized and the compressor 24 and its motor 25 are idle. As no refrigerant is stored in the reservoir 3|, both evaporators I0 and contain liquid refrigerant.

Assume now that the temperature in the chamber i8 rises sumciently to close the switch 45 for energizing the motor 25. Operation of the compressor 2l is initiated and vaporization of refrigerant within the evaporator Il is effected. Substantially no vaporization is effected at this time in the evaporator Ilias its temperature is lower than the temperature of vaporization corresponding to the pressure of the refrigerant in both evaporators IB and Il. Refrigerant condensed in the condenser 25 flows through the conduit 32, the reservoir 3|, the conduit 31 and the tube portion 35 to the manifold I1, conduit 23 and the evaporator Il as fast as it is condensed. The conduit 31 and the tube portion 35 define a relatively low resistance expansion element for the refrigerant, the prevailing pressure differential between the high and low sides at this time being relatively low. Operation of the compressor 2l continues until the temperature of the air in the chamber I8 is depressed to the value at which the thermostat switch 65 opens.

As the temperature within the chamber i3 rises to the value at which the thermostat l2 is adjusted to close the switches 44 and I5, the motor 25 and the solenoid 39 are energized, the latter effecting closure of the valve 38. Operation of the compressor first effects vaporization of refrigerant in the evaporator Il until it is exhausted, the vapor being condensed and collected in the reservoir 3| to a depth determined by the conduit 3B. This produces some cooling of the air in the chamber I8 but the amount of refrigerant in the evaporator I is soon exhausted and vaporization is initiated in the evaporator IIJ.

The compressor 2| operates to depress the pressure and temperature of the refrigerant within the evaporator Il), the vaporized refrigerant passing through the conduit 23 and evaporator Il to the suction conduit 21. The pressure differential between the high and low sides at this time is high and the high resistance expansion tube 33, including its portions 3| and 35, is effective to convey and expand the refrigerant. As the temperature Within the chamber I3 is depressed to the value at which the thermostat 42 opens its switches M and I5, the motor 25 and solenoid 39 are deenergized. Operation of the compressor 24 is, therefore, terminated and the valve 38 is opened by the tension spring 4|.

The purpose of opening the valve 38 at this time is to pass the stored liquid in the reservoir 3| to the low side of the system, otherwise it would vaporize in the reservoir 3| and pass to the low side as gas, resulting as a loss, extending the time for pressure equalization between the high and low sides and causing sweating of the reservoir structure. As the valve 38 opens, the stored liquid passes through the low resistance conduits 31 and tube portion 35, the manifold I1, conduit 23 to the evaporator Il. Some of this liquid is vaporized in the evaporator Il, which vaporization ceases as the pressure ncreases to a value determined by the temperature of the evaporator During this increase in pressure in the low side, it will be apparent that substantially no heating of the low temperature evaporator is eiected as it is filled with liquid which prevents gas from entering and condensing therein.

In the event that both thermostats close their respective switches at the same time, the low temperature thermostat 42 takes preference as the solenoid 39 is energized and storage of liquid on the high side is effected. The thermostat I3 may be given preference if desired by connecting the various elements as showrf'in Fig. 3.

In this embodiment, the low and high temperature thermostats are shown at 52 and 53, respectively. The low temperature thermostat 52 closes and opens a switch 5I in response to predetermined high and low temperatures and the thermostat 53 actuates a pair of switches 55 and 56, one of the latter being closed as the other is open. The switches 55 and 54 contol energize.- tion of the compressor motor 25 and close when their respective thermostats respond to predetermined high temperatures in their associated chambers. The switch 55 permits energizatlon of the solenoid 39 when the temperature reflected by the high temperature thermostat 53 ,is below the value at which it effects closure of the switch 55 and operation of the motor 25. At this time, energization of the solenoid 33 and motor 25 is effected by closure of the switch 54 in response to a predetermined high temperature obtaining within the low temperature chamber.

From the foregoing, it will be apparent that the connections shown in Fig. 3 give preference to the higher temperature thermostat 53 when both thermostats demand operation of the compressor 24. At this time, the switches 54 and 55 are closed whereby the motor 25 is energized but the solenoid 39 is deenergzed as the switch 56 is open. Accordingly, the valve 38 is open and both evaporators IIJ and contain refrigerant. As described heretofore, vaporization is effected in the higher temperature evaporator in this position of the apparatus.

I have referred throughout this specification to expansion devices of the capillary tube type. In defining a capillary tube, I desire it to be understood that it includes all forms of expansion devices having a passage that is relatively long with respect to its diameter or its flow area.

I have disclosed a form of refrigerating system to which my invention may be applied, but it will be understood that it is not so limited and may be applied to other systems of either the single or the multiple temperature type wherein capillary tubes are employed and where it is desired that refrigerant is delivered from the high to the low sides at different selected rates.

While I have shown my invention in several forms, it will be obvious to those skilled in the art that it is not so limited, but is susceptible of various other changes and modifications without departing from the spirit thereof, and I desire, therefore, that only such limitations shall be placed thereupon as are imposed by the prior art or as are specically set forth in the appended claims.

What I claim is:

1. In refrigerating apparatus, the combination of an evaporator structure, means for withdrawing refrigerant vaporized in the evaporator structure, means for condensing the withdrawn refrigerant, means for conveying the condensed refrigerant to the evaporator structure, said conveying means including first and second capillary expansion means having different resistances to refrigerant flow and means for selecting the expansion means that is effective to convey the refrigerant to the evaporator structure and means for storing and withholding from the evaporator structure a predetermined quantity of condensed refrigerant when the capillary expansion means of greater resistance is rendered effective and releasing said predetermined quantity of said condensed refrigerant to the evaporator structure when the capillary expansion means of lesser resistance is rendered effective.

2. 1n refrigerating apparatus, the combination of an evaporator structure, means for withdrawing vaporous refrigerant from the evaporator structure, means for condensing the withdrawn refrigerant, and means for conveying the condensed refrigerant to the evaporator structure, said conveying means defining a pair of elongated passages having different resistances to the flow of refrigerant, and means for selectively rendering one or the other of the passages effective to convey the refrigerant and means for withholding from the evaporator structure a predetermined quantity of condensed refrigerant when the elongated passage oi' greater resistance is rendered effective and releasing said predetermined quantity of condensed refrigerant to the evaporator structure when the elongated passage of lesser resistance is rendered effective.

3. In refrigerating apparatus, the combination with relatively low and high temperature evaporators and means for condensing refrigerant vaporized in the evaporators, of means for conveying the condensed refrigerant to the evaporators in such manner that it ows into the low temperature evaporator by preference and thence into the higher temperature evaporator; said conveying means including a pair of elongated conduits having different reslstances to the flow of refrigerant and means for selecting the conduit that is effective for conveying the refrigerant.

4. In refrigerating apparatus, the combination with relatively low and high temperature evaporators and means for condensing refrigerant vaporlzed in the evaporators. of means for conveying the condensed refrigerant to the evaporators in such manner that it flows into the low temperature evaporator by preference and thence into the higher temperature evaporator; said conveying means including means for storing and withholding from circulation a predetermined amount of condensed refrigerant at which time condensed refrigerant is delivered for vaporization in the low temperature evaporator only, means for releasing the withheld refrigerant in the storing means whereby condensed refrigerant is delivered for vaporization in the higher temperature evaporator, a first expansion device for conveying the condensed refrigerant to the evaporators during periods when refrigerant is stored in the refrigerant storage means and a second expansion device for conveying refrigerant to the evaporators during periods when storage of refrigerant is not effected in the refrigerant storage means and means for selecting the expansion device that is effective for conveying the refrigerant to the evaporators.

5. In refrigerating apparatus. the combination with relatively high and low temperature evaporators, and means for condensing refrigerant vaporized in the evaporators. of means for conveying the condensed refrigerant to the evaporators in such manner that the refrigerant flows by preference into the low temperature evaporator until it is lled and thence into the higher temperature evaporator. said refrigerant conveying means including a container in which a predetermined quantity of condensed refrigerant may be stored and withheld from circulation at which time the low temperature evaporator only contains condensed refrigerant, means for controlling the storage of refrigerant in the container, conduit means having relatively high resistance for conveying refrigerant from the container to the evaporators during periods when refrigerant is stored in the container, and a second conduit means having relatively low resistance for conveying refrigerant from the container to the evaporators when storage of refrigerant in the container is not effected.

6. In refrigerating apparatus, the combination of relatively high and low temperature evaporators so connected that condensed refrigerant admitted thereto flows by preference into the low temperature evaporator and thence into the higher temperature evaporator, means for condensing refrigerant vaporized in the evaporators. a container for receiving condensed refrigerant from the condensing means, a relatively high resistance expansion conduit communicating with an upper portion of the container for conveying refrigerant therefrom to the evaporators, a relatively low resistance expansion conduit communicating with a lower portion of the container for conveying refrigerant therefrom to the evaporator,` a valve biased to its open position controlling the passage of refrigerant through said low resistance conduit, and thermostats associated with each evaporator and being responfor effecting operation of the condensing means and being responsive to predetermined low temperatures thereof for terminating operation of the condensing means, said thermostat assoclated with the low temperature evaporator being eifective to close said biased valve during periods when it effects operation of the condensing means.

7. The combination as claimed in claim 6 having means for rendering the thermostat associated with the low temperature evaporator ineffective to control the compressor and the valve during periods when the thermostat associated with the high temperature evaporator effects operation of the condensing means.

8. In refrigeratlng apparatus, the combination of an evaporator structure, means for condensing refrigerant vaporized in said structur a conduit having relatively high resistance for conducting the condensed refrigerant from the condensing means to the evaporator structure, a second conduit having relatively low resistance for conveying condensed refrigerant and connected to said rst conduit intermediate its ends whereby a by-pass is defined in parallel with a portion of the high resistance conduit, and means for controlling the passage of refrigerant through Said low resistance conduit and means for storing and withholding from the evaporator structure a predetermined quantity of condensed re frigerant during periods when the refrigerant is conveyed by the high resistance conduit and releasing said predetermined quantity of said condensed refrigerant to the evaporator structure during periods when passage of refrigerant is effected through the low resistance conduit.

9. The combination as claimed in claim 8 wherein said refrigerant controlling means is thermostatically actuated.

10. In refrigeration apparatus, the combination of relatively high and low temperature evaporators so connected that condensed refrigerant admitted thereto flows by preference into the low temperature evaporator and thence into the higher temperature evaporator, means for condensing the refrigerant vaporized in the evaporators, a conduit having relatively high resistance for conducting the condensed refrigerant from the condensing means to the evaporators, a second amasar conduit for conveying condensed refrigerant and having an end thereof connected to an intermediate portion of said first conduit and deilning a by-pass around a portion of the rst conduit, and valve means controlling the passage of refrigerant in said second conduit.

11. In refrigeration apparatus, the combination of relatively high and low temperature evaporators so connected that condensed refrigerant admitted thereto flows by preference into the low temperature evaporator and thence into the higher temperature evaporator, means for condensing the refrigerant vaporized in the evaporators, a conduit having relatively high resistance for conducting the condensed refrigerant from the condensing means to the evaporators, a second conduit for conveying condensed refrigerant and having an end portion thereof connected to an intermediate portion of said first conduit and deiining a by-pass around a portion of the i'lrst conduit, a valve for controlling the passage of refrigerant in said second conduit and rst and second thermostats responsive to the temperatures of the respective low and high temperature evaporators for controlling the operation of the refrigerant condensing means, said thermostat associated with the low temperature being eective to close said valve during periods when it eilects operation of the refrigerant condensing means and said valve being open at all other times.

CERTIFICATE 0F Patent No. 2,135,961

LESLIE s. r1.

12. In refrigeration apparatus, the combination of relatively high and low temperature evaporators so connected that condensed refrigerant admitted thereto flows by preference into the low temperature evaporator and thence into the higher temperature evaporator, means for condensing the refrigerant vaporized in the evaporators, a conduit having relatively high resistance for conducting the condensed refrigerant from the condensing means to the evaporators, a second conduit for conveying condensed refrigerant and having an end portion thereof connected to an intermediate portion of said first conduit and defining a by-pass around a portion of the first conduit, a valve for controlling the passage of refrigerant in said second conduit and iirst and second thermostats responsive to the temperatures of the respective low and high temperature evaporators for controlling the operation of the refrigerant condensing means, said thermostat associated with the low temperature evaporator being effective to close said valve during periods when it effects operation of the refrigerant condensing means, said valve being open at all other times, and means for rendering said thermostat associated with the low temperature evaporator inactive to control the valve during periods when the thermostat associated with the higher temperature evaporator eifects operation of the refrigerant condensing means.

LESLIE B. M. BUCHANAN.

CORRECTION.

October 25 1938.

BUCHANAN.

It is hereby certified that error appears in the printed specification of the above numbered patentrequiring c column, comma; page h., claim B, strike out "and" orrection as follows: .Page 5, second line 67, claim l strike out the word "and" and insert instead a first column, line 1l, claim 2, and second column, line 52, and that the said Lettera Patent should be read with this correction therein that the same may conform to the record of the case in the Patent Office.

signed and sealed this 6th ,dayef December, A. D. 1958.

(Seal) Henry Van Arsdale Acting Commissioner of, Patents.

Cil

amasar conduit for conveying condensed refrigerant and having an end thereof connected to an intermediate portion of said first conduit and deilning a by-pass around a portion of the rst conduit, and valve means controlling the passage of refrigerant in said second conduit.

11. In refrigeration apparatus, the combination of relatively high and low temperature evaporators so connected that condensed refrigerant admitted thereto flows by preference into the low temperature evaporator and thence into the higher temperature evaporator, means for condensing the refrigerant vaporized in the evaporators, a conduit having relatively high resistance for conducting the condensed refrigerant from the condensing means to the evaporators, a second conduit for conveying condensed refrigerant and having an end portion thereof connected to an intermediate portion of said first conduit and deiining a by-pass around a portion of the i'lrst conduit, a valve for controlling the passage of refrigerant in said second conduit and rst and second thermostats responsive to the temperatures of the respective low and high temperature evaporators for controlling the operation of the refrigerant condensing means, said thermostat associated with the low temperature being eective to close said valve during periods when it eilects operation of the refrigerant condensing means and said valve being open at all other times.

CERTIFICATE 0F Patent No. 2,135,961

LESLIE s. r1.

12. In refrigeration apparatus, the combination of relatively high and low temperature evaporators so connected that condensed refrigerant admitted thereto flows by preference into the low temperature evaporator and thence into the higher temperature evaporator, means for condensing the refrigerant vaporized in the evaporators, a conduit having relatively high resistance for conducting the condensed refrigerant from the condensing means to the evaporators, a second conduit for conveying condensed refrigerant and having an end portion thereof connected to an intermediate portion of said first conduit and defining a by-pass around a portion of the first conduit, a valve for controlling the passage of refrigerant in said second conduit and iirst and second thermostats responsive to the temperatures of the respective low and high temperature evaporators for controlling the operation of the refrigerant condensing means, said thermostat associated with the low temperature evaporator being effective to close said valve during periods when it effects operation of the refrigerant condensing means, said valve being open at all other times, and means for rendering said thermostat associated with the low temperature evaporator inactive to control the valve during periods when the thermostat associated with the higher temperature evaporator eifects operation of the refrigerant condensing means.

LESLIE B. M. BUCHANAN.

CORRECTION.

October 25 1938.

BUCHANAN.

It is hereby certified that error appears in the printed specification of the above numbered patentrequiring c column, comma; page h., claim B, strike out "and" orrection as follows: .Page 5, second line 67, claim l strike out the word "and" and insert instead a first column, line 1l, claim 2, and second column, line 52, and that the said Lettera Patent should be read with this correction therein that the same may conform to the record of the case in the Patent Office.

signed and sealed this 6th ,dayef December, A. D. 1958.

(Seal) Henry Van Arsdale Acting Commissioner of, Patents.

Cil 

